Collision avoidance system and collision avoidance method

1. A collision avoidance system comprising: a driver state detection unit configured to detect a state of a driver of a host vehicle; an environment detection unit configured to detect an environment in which the host vehicle is traveling; an external warning device configured to perform an external warning operation that warns another vehicle traveling in a vicinity of the host vehicle; an internal warning device configured to perform an internal warning operation that warns the driver of the host vehicle; and a control unit configured to control the external warning device and the internal warning device on a basis of the state of the driver detected by the driver state detection unit, the control unit configured to set a predetermined time period on a basis of the environment detected by the environment detection unit, and control the external warning device and the internal warning device, on the basis of the state of the driver, so as to perform the internal warning operation after the external warning operation has been performed and after the predetermined time period has further elapsed.

2. The collision avoidance system according to claim 1 , wherein the environment detection unit is configured to detect, as the environment, at least one of a state of a road surface on which the host vehicle is traveling, a time of day or the like at which the host vehicle is traveling, weather information of an area in which the host vehicle is traveling, and a travel speed of the host vehicle.

3. The collision avoidance system according to claim 1 , further comprising: a distance measurement unit configured to measure a distance between the host vehicle and the other vehicle, wherein the control unit is configured to control the external warning device and the internal warning so as to perform the external warning operation and the internal warning operation when the distance measured by the distance measurement unit is within a predetermined range.

4. The collision avoidance system according to claim 1 , wherein the other vehicle includes a following vehicle traveling behind the host vehicle.

5. The collision avoidance system according to claim 1 , wherein the driver state detection unit is configured to detect a state in which the driver is looking aside.

6. The collision avoidance system according to claim 5 , wherein the driver state detection unit includes an image capturing unit configured to detect an image of the driver and detect the state of the driver looking aside on a basis of the image of the driver.

7. The collision avoidance system according to claim 1 , wherein the external warning operation includes at least one of a predetermined display operation directed at the other vehicle and a predetermined sound outputting operation directed at the other vehicle.

8. The collision avoidance system according to claim 1 , wherein the external warning operation includes an operation of transmitting, to the other vehicle, a signal for activating another warning device provided in the other vehicle.

9. A collision avoidance method comprising: detecting a state of a driver of a host vehicle; performing an external warning operation that warns another vehicle traveling in a vicinity of the host vehicle; performing an internal warning operation that warns the driver of the host vehicle; detecting an environment in which the host vehicle is traveling; and setting a predetermined time period on a basis of the environment, wherein the performing of the internal warning operation is after the performing of the external warning operation and after the predetermined time period has elapsed.

10. The collision avoidance system according to claim 2 , further comprising: a distance measurement unit configured to measure a distance between the host vehicle and the other vehicle, wherein the control unit is configured to control the external warning device and the internal warning so as to perform the external warning operation and the internal warning operation when the distance measured by the distance measurement unit is within a predetermined range.

11. The collision avoidance system according to claim 10 , wherein the other vehicle includes a following vehicle traveling behind the host vehicle.

12. The collision avoidance system according to claim 11 , wherein the driver state detection unit is configured to detect a state in which the driver is looking aside.

13. The collision avoidance system according to claim 12 , wherein the driver state detection unit includes an image capturing unit configured to detect an image of the driver and detect the state of the driver looking aside on a basis of the image of the driver.

14. The collision avoidance system according to claim 13 , wherein the external warning operation includes at least one of a predetermined display operation directed at the other vehicle and a predetermined sound outputting operation directed at the other vehicle.

15. The collision avoidance system according to claim 14 , wherein the external warning operation includes an operation of transmitting, to the other vehicle, a signal for activating another warning device provided in the other vehicle.